Multicontact crystal detector



w. s. FREESLAND MULTICONTACT CRYSTAL DETECTOR Filed on. 2, 1922 WilsonS. I'reesland.

3 NVENTOR 1 1 I W W VITNESS:

Patented May 25, 1926.

WILSON s. FREESLAND, or NORFOLK, vrnernm.

MULTICONTACT cnYs r I. nnrncron.

Application filed October 2, 1922. Serial No. 591,904.

This invention relates to multicontact crystal detectors, and theprincipal object of the invention is to reduce to a minimiun theinterference caused in the present day crystal radio sets by the burningout or losing of the sensitive spot on the crystal.

Another object is to produce a device of this nature wherein amultiplicity of circuits are instantly available for each crystal used.

Another object is to produce a device of this nature which shall be ofsimple construction, cheap to manufacture, and highly efficient for thepurpose for which it is designed,

With these and other objects in view which will become more apparent asthis specification proceeds, the invention resides in certain novelfeatures of construction and combination and arrangement of parts, theessential features of which are hereinafter fully described, areparticularly pointed out in the appended claim and are illustrated inthe accompanying drawing, in whichi Fig. 1is a top plan view of mymulticontact crystal detector.

Fig. 2-is a side elevation of the same,

parts being taken away for the sake of sage will be lost.

clearness. I I

Fig. 3is a bottom plan v1ew of the device.

Like characters of reference refer to like parts in all views.

It is well known to radiousers that the rectifying crystals have anunknown number of sensitive spots which must be picked or selected bycareful adjustment and on periment. After a certain time of continuoususeof one spot,it becomes insensitive which necessitates are-adjustment. Oftentimes the burning out or losing of the sensitivespot will occur in the middle of a message, causing confusion or perhapsthe entire loss of the meaning of the message. The present inventioncontemplates elimination of these difiiculties by providing means forinstantly switching from one to another of a multiplicity of previouslylocated sensitive spots on the crystal.

Referring to the drawing in detail, 10

represents a base plate which may be of h,

any suitable insulating material such as hard rubber, and molded to theform shown in the accompanying drawing. The base 10 carries the usualbinding posts 11 and 12; Thebinding post 12 is connected by a wire 13with one of the adjusting screws 14- which hold the crystal 15 in itsadjusted position in the crystal cup 16. I I j 7 The binding post 11 isconnected by a wire 17 with a rotaryswitch 18 having a finger 19 adaptedto be moved over a plurality of contacts 20. Connected to each ,of thecontacts 20 is a wire or lead 21 which passes through a respectiveaperture'in the base 10 and forward to the crystal cup where it passesvertically upwardly through the base 10 and into the cup 16, forming aplurality of contact points 22.

In use, the operator drops the crystal 15 into the crystal cup 16 andthen adjusts it by experiment until a plurality of the points '22 touchsensitive spots on the "detector. hen the device is then operating, andthe sensitive spot in use burns out, the operator can rapidly move theswitch finger 19 over the various contacts 20 until a new sensitive spotis brought into play, and so quickly and easilythat little or nothing ofthe mes-' W hile I have described what I deem to be the most desirableembodiment of my invention, 'I do not wish to limit myself'to the exactdetails ofconstruction herein set forth, nor to anything less than thewhole of my invention; as set forth in theappe-nded claim.

' r I claim r I Armultiple contact detector for radio comprising arectangular base having an upstanding cup formed thereon, a plurality ofcontacts arranged in an are about a com-' men-center, said base providedwith a plurality of openings opening upwardly into said cup, wiresattached tosaid contacts and extendingthrough said openings into saidcup, 21. metal crystal within said cup, and

means detachably mounting said crystal within the cup and innon-supporting en" gagement with said wires.

In testimony whereof I atlix my signature WILSON s. FREESLAND.

